Cable Winch Tension Control via Sea State Feedback
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Solution Overview
Problem
Existing cable winch systems for davit and crane systems on watercraft inadequately manage cable tension fluctuations due to sea movements, leading to potential damage from excessive force variations during tender boat operations in rough seas, and are often complex and costly.
Innovation Solution
A method involving a sea state follow-up control system that measures actual cable force, direction, and speed, and adjusts motor torque and rotation to maintain a preset target force, using a force transducer, rotary encoder, and motor controller to regulate cable pull, ensuring consistent tension regardless of wave movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional cable winch system with brake and fixed position control is used, then the device structure is simple, but the cable tension fluctuates significantly due to sea movements causing potential damage
Solution Approach 1:
The patent implements dynamic position control where the winch drum rotates automatically in response to cable tension changes caused by sea movements. The control system continuously adjusts the drum position to maintain constant cable tension, transforming the static brake-held system into a dynamic self-regulating system that adapts to wave conditions.
Solution Approach 2:
The patent employs a feedback control mechanism where a force sensor measures actual cable tension, compares it to the target tension value, and uses the deviation signal to control the motor-driven winch drum. This closed-loop feedback system automatically compensates for tension fluctuations caused by sea state changes.
2Reliability
If an auxiliary arm compensation system is added to compensate for height fluctuations, then cable tension stability improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces the complex mechanical auxiliary arm compensation system with an electric motor-driven winch drum control system. Instead of using additional mechanical linkages and arms to compensate for height changes, the system uses an electric motor to dynamically adjust the cable payout, achieving the same tension stabilization function with simpler mechanical structures.
Solution Approach 2:
The patent changes the control parameter from fixed mechanical positioning to dynamic electrical control. By using a motor-driven system controlled by electrical signals based on force sensor feedback, the system can rapidly adjust cable tension in response to sea movements, providing superior response characteristics compared to mechanical compensation systems.
3Adaptability or versatility
If manual operation with buttons or joysticks is used, then the device structure is simple, but the response to sea conditions is inadequate and requires constant operator attention
Solution Approach 1:
The patent implements a self-regulating control system where the winch automatically adjusts cable tension in response to sea conditions without requiring continuous operator intervention. The force sensor and control unit work together to automatically compensate for wave-induced tension changes, allowing the system to service itself and maintain optimal tension autonomously.
Solution Approach 2:
The patent employs automatic feedback control where the force sensor continuously monitors cable tension and the control unit automatically adjusts motor output to maintain target tension. This eliminates the need for manual operation while providing superior adaptability to changing sea conditions, as the system responds instantaneously to tension changes without human reaction time delays.
Data Source
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AI summary
The invention relates to a method for regulating a cable pulling force of a cable winch for a davit system or a crane system of a watercraft as part of a sea state sequence control, comprising the steps of: applying a trailer load to the cable; measuring an actual cable force; determining an actual direction of rotation and an actual rotational speed of the cable winch; transmitting the actual cable force, the actual direction of rotation and the actual rotational speed to a motor control assigned to the cable winch; determining a deviation of the actual cable force from a preset target cable force; to achieve the target cable force: determining a target motor torque and a target motor rotational direction of a motor of the cable winch from the determined cable force deviation, the actual direction of rotation and the actual rotational speed; controlling the motor with the target motor torque and the target motor rotational direction by the motor control.